198 research outputs found
Possible manifestation of spin fluctuations in the temperature behavior of resistivity in Sm_{1.85}Ce_{0.15}CuO_4 thin films
A pronounced step-like (kink) behavior in the temperature dependence of
resistivity is observed in the optimally-doped
thin films around and attributed to
manifestation of strong spin fluctuations induced by moments with the
energy . In addition to fluctuation
induced contribution due to thermal broadening effects (of the
width ), the experimental data are found to be well fitted
accounting for residual (zero-temperature) , electron-phonon and electron-electron contributions. The
best fits produced , ,
, and for estimates of the plasmon frequency, the
impurity scattering rate, electron-phonon coupling constant, and the Fermi
energy, respectively.Comment: 6 pages (REVTEX4), 2 EPS figures; accepted for publication in JETP
Letter
Irreversibility line and low-field grain-boundary pinning in electron-doped superconducting thin films
AC magnetic susceptibilities of electron-doped Pr_{1.85}Ce_{0.15}CuO_4 (PCCO)
and Sm_{1.85}Ce_{0.15}CuO_4 (SCCO) granular thin films have been measured as a
function of temperature and magnetic-field strength. Depending on the level of
homogeneity of our films, two different types of the irreversibility line (IL)
defined as the intergrain-loss peak temperature in the imaginary part of
susceptibility have been found. The obtained results are described via the
critical-state model taking into account the low-field grain-boundary pinning.
The extracted pinning-force densities in more granular SCCO films turn out to
be four times larger than their counterparts in less granular PCCO films
Probing pairing symmetry of Sm_{1.85}Ce_{0.15}CuO_4 via highly-sensitive voltage measurements: Evidence for strong impurity scattering
Using a highly-sensitive home-made mutual-inductance technique, temperature
profiles of the magnetic penetration depth in the optimally-doped
thin films have been extracted. The low-temperature
behavior of is found to be best-fitted by linear and quadratic laws above and below ,
respectively, which clearly indicates the presence of d-wave pairing mechanism
dominated by strong paramagnetic scattering at the lowest temperatures. The
best fits produce and
for the estimates of the nodal gap parameter and impurity scattering rate
Investigation of microwave dielectric relaxation process in the antiferroelectric phase of NaNbO3 ceramics
This letter reports microwave dielectric measurements performed in the
antiferroelectric phase of NaNbO3 ceramics from 100 to 450 K. Remarkable
dielectric relaxations were found within the antiferroelectric phase and in the
vicinity of ferroelectric-antiferroelectric phase transition. Such dielectric
relaxation process was associated with relaxations of polar nanoregions with
strong relaxor-like characteristic. In addition, the microwave dielectric
measurements also revealed an unexpected and unusual anomaly in the relaxation
strength, which was related to a disruption of the antiferroelectric order
induced by a possible AFE-AFE phase transition.Comment: 4 pages and 4 figures - Paper accepted for publication in the Solid
State Communication
Elastic properties of polycrystalline YBa_2Cu_3O_7: Evidence for granularity induced martensitic behavior
In this work we present the study of the elastic properties of
polycrystalline samples of superconducting YBa_2Cu_3O_7 prepared by the sol-gel
method. The quality of all samples was checked by x-ray diffraction and
scanning electronic microscopy while their physical properties were verified by
transport and magnetic measurements. The elastic study was performed using the
standard pulse-echo technique through measuring the phase velocity and the
attenuation of ultrasonic waves (in the range of a few MHz) as a function of
temperature. We have focused this study on the low temperatures interval (T <
200K). The obtained results show a strong hysteretic behavior in the ultrasonic
attenuation (in addition to usually observed hysteretic behavior for the
velocity) which strongly supports the existence of a martensitic-like phase
above the superconducting critical temperature T_C. We argue that this peculiar
behavior can be attributed to the granularity present in the samples.Comment: Physica C (in press
The effect of service satisfaction and spiritual well-being on the quality of life of patients with schizophrenia.
Quality of life (QOL) has been considered an important outcome measure in psychiatric research and determinants of QOL have been widely investigated. We aimed at detecting predictors of QOL at baseline and at testing the longitudinal interrelations of the baseline predictors with QOL scores at a 1-year follow-up in a sample of patients living in Residential Facilities (RFs). Logistic regression models were adopted to evaluate the association between WHOQoL-Bref scores and potential determinants of QOL. In addition, all variables significantly associated with QOL domains in the final logistic regression model were included by using the Structural Equation Modeling (SEM). We included 139 patients with a diagnosis of schizophrenia spectrum. In the final logistic regression model level of activity, social support, age, service satisfaction, spiritual well-being and symptoms' severity were identified as predictors of QOL scores at baseline. Longitudinal analyses carried out by SEM showed that 40% of QOL follow-up variability was explained by QOL at baseline, and significant indirect effects toward QOL at follow-up were found for satisfaction with services and for social support. Rehabilitation plans for people with schizophrenia living in RFs should also consider mediators of change in subjective QOL such as satisfaction with mental health services
Magnetoresistance in Sn-Doped In2O3Nanowires
In this work, we present transport measurements of individual Sn-doped In2O3nanowires as a function of temperature and magnetic field. The results showed a localized character of the resistivity at low temperatures as evidenced by the presence of a negative temperature coefficient resistance in temperatures lower than 77 K. The weak localization was pointed as the mechanism responsible by the negative temperature coefficient of the resistance at low temperatures
The giardial VPS35 retromer subunit is necessary for multimeric complex assembly and interaction with the Vacuolar protein sorting receptor
The retromer is a pentameric protein complex that mediates the retrograde transport of acid hydrolase receptors between endosomes and the trans-Golgi network and is conserved across all eukaryotes. Unlike other eukaryotes, the endomembrane system of Giardia trophozoite is simple and is composed only of the endoplasmic reticulum and peripheral vesicles (PVs), which may represent an ancient organellar system converging compartments such as early and late endosomes and lysosomes. Sorting and trafficking of membrane proteins and soluble hydrolases from the endoplasmic reticulum to the PVs have been described as specific and conserved but whether the giardial retromer participates in receptor recycling remains elusive. Homologs of the retromer Vacuolar Protein Sorting (Vps35p, Vps26p, and Vps29p) have been identified in this parasite. Cloning the GlVPS35 subunit and antisera production enabled the localization of this protein in the PVs as well as in the cytosol. Tagged expression of the subunits was used to demonstrate their association with membranes, and immunofluorescence confocal laser scanning revealed high degrees of colabeling between the retromer subunits and also with the endoplasmic reticulum and PV compartment markers. Protein-protein interaction data revealed interaction between the subunits of GlVPS35 and the cytosolic domain of the hydrolase receptor GlVps. Altogether our data provide original information on the molecular interactions that mediate assembly of the cargo-selective retromer subcomplex and its involvement in the recycling of the acid hydrolase receptor in this parasite.Fil: Miras, Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra; ArgentinaFil: Merino, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra; ArgentinaFil: Gottig Schor, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Ropolo, Andrea Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra; ArgentinaFil: Touz, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra; Argentin
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